1. Field of the Invention
The present invention relates generally to treating a pavement surface and, more particularly, to a method and apparatus for treating a pavement surface which functions to repair points of distress in the pavement and provide a durable wearing surface in a single pass.
2. Description of Related Art
Modern roadways are usually paved in order to provide a more durable surface for vehicular traffic. Over time, existing roadways inevitably become worn and in need of repair. For example, cracks may develop so that the surface is no longer water resistant and deterioration of the roadway occurs at an accelerated pace. Alternatively, the surface may become overly smooth so that the skid resistance of the roadway is adversely affected. In either event, the existing roadway surface becomes dangerous to drive on and therefore presents a public safety concern. Accordingly, existing roadways should be periodically resurfaced or repaved in the course of proper maintenance.
As explained in U.S. Pat. No. 5,895,173 to O""Brien et al., one type of resurfacing process (known in the industry as xe2x80x9cchipsealingxe2x80x9d) involves the dropping of aggregate material into a previously applied layer of adhesive material so as to bind the aggregate material to the surface. Typically, the two steps of the chipsealing process are performed by two different machines, an asphalt distributor and a chipspreader, making two separate passes over the same portion of roadway. While improvements have been made to overcome some of the inherent deficiencies of this process, including the ability to perform both steps in a single pass, it is a continuing goal in the industry to accelerate the material break and cure time of the completed product so as to permit traffic to resume use as soon as possible. Further, it is desired that additional improvements in the areas of reflective cracking and waterproofing over the current chipsealing process be achieved.
Accordingly, it is a primary object of the present invention to provide a method of treating a pavement surface which can be utilized as an interlayer prior to asphalt overlays or as a final preventive maintenance surface.
It is another object of the present invention to provide a method of treating a pavement surface that produces a membrane that dissipates crack propagation forces, waterproofs the pavement, and is durable to traffic.
It is still another object of the present invention to provide a method of treating a pavement surface that reduces reflective cracking and provides a textured surface for asphalt paving.
Yet another object of the present invention is to provide a method of treating a pavement surface that produces a complete product in one pass, thereby reducing construction delays and costs.
Another object of the present invention is to provide a method of treating a pavement surface that accelerates the material break and cure time of the completed product, thereby permitting use of the pavement surface more quickly.
Still another object of the present invention is to provide a method of treating a pavement surface that improves adhesion between the completed product and the existing pavement surface.
These objects and other features of the present invention will become more readily apparent upon reference to the following description when taken in conjunction with the following drawings.
In accordance with a first aspect of the present invention, a method of treating a pavement surface is disclosed as including the following steps: applying a layer of bituminous sealant at a predetermined temperature and application rate on the pavement surface; applying a layer of bituminous emulsion at a predetermined temperature and application rate on the layer of bituminous sealant, wherein a thermal reaction occurs between the bituminous sealant and the bituminous emulsion so as to accelerate a material break and cure time for the layers; and, providing a layer of aggregate particles at a predetermined application rate on the layers of bituminous sealant and bituminous emulsion during the thermal reaction. The steps of the method are performed successively along a particular direction of advance at a rate which permits them to be accomplished within a predetermined time period. Additional steps of compacting the layers and/or applying an asphalt layer thereon may also be performed.
In accordance with a second aspect of the present invention, a surface treatment for pavement is disclosed as including a layer of bituminous sealant applied to the pavement at a predetermined temperature and application rate so as to fill substantially all cracks and voids in the pavement and constitutes a substantially continuous surface thereon, a layer of bituminous emulsion applied to the layer of bituminous sealant at a predetermined temperature and application rate, and a layer of aggregate particles provided on the layer of bituminous emulsion at a predetermined application rate, wherein the surface treatment absorbs underlying crack movement and forces in the pavement.
In accordance with a third aspect of the present invention, an apparatus for treating a pavement surface with a plurality of layers in a single pass is disclosed as including: a chassis having a forward end and a rear end; a plurality of rolling means spaced longitudinally along the chassis for supporting the chassis so it can roll along a particular direction of advance; means for moving the chassis along the direction of advance; a first storage tank mounted on the chassis for containing bituminous sealant; a second storage tank mounted on the chassis for containing bituminous emulsion; a main hopper mounted on the chassis for storing aggregate particles; a first mechanism in flow communication with the first storage tank for applying a layer of bituminous sealant at a predetermined temperature and application rate on the pavement surface; a second mechanism in flow communication with the second storage tank for applying a layer of bituminous emulsion at a predetermined temperature and application rate on the layer of bituminous sealant, wherein a thermal reaction occurs between the bituminous sealant and the bituminous emulsion so as to accelerate a material break and cure time for the layers; a third mechanism in flow communication with the main hopper for providing a layer of aggregate particles at a predetermined application rate on the layers of bituminous sealant and bituminous emulsion during the thermal reaction.